Home Biomarkers Absolute Large Unstained Cell

Absolute Large Unstained Cell

CBC Biomarker

Sample Needed

Collection Type: Blood

Body System

Related System: CBC

Overview

Large Unstained Cells (absolute count) (often abbreviated LUC# or ALUC) are a component reported by modern automated complete blood count (CBC) analyzers. The instrument flags and counts cells that are larger than typical lymphocytes and that do not take up the usual staining pattern used by the analyzer a heterogeneous group that can include atypical/reactive lymphocytes, blasts (immature white cells), immature granulocytes, large granular lymphocytes, plasma cells or monocytes. The test measures the absolute number of these large unstained cells in peripheral blood. Elevated counts may be seen with viral infections (e.g., infectious mononucleosis), severe bacterial infections, allergic/drug reactions, and hematologic malignancies (leukemia, lymphoma, myelodysplasia). Symptoms prompting testing include fever, unexplained lymphadenopathy, persistent fatigue, easy bruising/bleeding, recurrent infections, or abnormal CBC flags. Children often show higher reactive lymphocytes with viral infections; elderly patients or those on immunosuppressive therapy may show different patterns. Reference ranges and clinical significance can vary with age, recent vaccination, and pregnancy.

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Test Preparation

No special preparation is required

Why Do I Need This Test

Profile: Included as part of a Complete Blood Count (CBC) with automated differential.
Symptoms prompting the test: fever, swollen lymph nodes, unexplained fatigue, bleeding/bruising, recurrent or severe infections.
Conditions assessed: reactive/atypical lymphocytosis from infections, drug reactions, and monitoring/diagnosis of hematologic malignancies (leukemia, lymphoma).
Reasons for abnormal levels: acute viral infection, severe inflammation, medication/drug reaction, or presence of malignant/immature white cells.
Biological meaning: elevated ALUC suggests increased immature or atypical large white cells (reactive or neoplastic); very low or absent values are usually not specific.
Behaviors/lifestyle: recent infections, vaccinations, or certain drugs can raise counts.
Family history: a family history of leukemia, lymphoma, or inherited immunodeficiency may prompt closer evaluation.

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Understanding Test Results

Values within 0.00–0.10 x10^9/L are considered normal.
Mild elevation (approximately 0.11–0.50 x10^9/L or ~110–500 cells/µL) commonly reflects reactive/atypical lymphocytes from recent viral infections (e.g., EBV, CMV), acute bacterial infections, or drug/allergic reactions.
Moderate elevations (about 0.51–1.5 x10^9/L) raise concern for more pronounced reactive processes or a persistent abnormal population and warrant blood smear review and clinical correlation.
Marked elevations (>1.5 x10^9/L) increase the likelihood of a pathologic process such as acute leukemia, lymphoma with circulating malignant cells, or a myelodysplastic/ myeloproliferative disorder and require urgent hematology evaluation (smear review, flow cytometry, bone marrow as indicated).
A value of zero is not usually significant by itself; very low counts in the setting of pancytopenia or bone marrow failure indicate reduced marrow production and need further workup.
Interpretation should always consider the instrument’s reference range and a peripheral smear review for definitive characterization.

Normal Range

0.00-0.10 x10^9/L OR 0-100 cells/µL

FAQs

Q: What are absolute large unstained cells?

A: Absolute large unstained cells (absolute LUC) is the measured number of unusually large peripheral blood cells that fail to take up standard staining on automated hematology analyzers. Normally very low or absent; increases occur with reactive or immature cells—e.g., atypical or activated lymphocytes, blasts or monocytes—seen in viral infections, inflammation, or hematologic disorders. Elevated LUC prompts smear review and clinical correlation.

Q: What does it mean when your Luc is high?

A: A high LUC (large unstained cell) count means your automated blood test detected more atypical or immature white blood cells than usual. Causes include viral infections, strong inflammatory or immune responses, and rarerly blood cancers like leukemia. It's a nonspecific alert that needs clinical correlation, a manual peripheral‑smear review, and possibly further tests or hematology referral to identify the exact cause.

Q: What is BA in a blood test?

A: BA on a blood test most often means either the absolute basophil count (a type of white blood cell involved in allergic and inflammatory responses) or, in liver-related panels, blood bile acids (markers of bile flow). Abnormal basophil counts suggest allergy, infection or hematologic issues; elevated bile acids indicate cholestasis or liver dysfunction and need further clinical evaluation.

Q: What are unstained cells?

A: Unstained cells are live or fixed cells examined without added dyes or histological stains. Because they retain native color and structure, they’re useful for observing morphology and viability without chemical alteration. Under bright-field microscopy they’re largely transparent, so specialized optics (phase-contrast, DIC) or noninvasive imaging are used. Absence of stain preserves function but reduces contrast and hides many subcellular details.

Q: What is the normal range of Luc?

A: LUC (large unstained cells) is normally very low. Typical reference ranges: LUC% about 0–1% (commonly 0–0.5%) and absolute LUC about 0.00–0.03 ×10^9/L. Ranges vary by laboratory and analyzer, so compare results with the lab’s reference interval and discuss any abnormal values with your healthcare provider. Mild elevations can reflect infection, inflammation, or sample artifact and may need follow-up.

Q: What's the difference between stained and unstained cells?

A: Stained cells are treated with dyes or labels that increase contrast and reveal structures, specific molecules or dead/live status (e.g., Gram, fluorescent, immunostains), often after fixation. Unstained cells are viewed in their native, usually live state with low intrinsic contrast; specialized optics (phase contrast, DIC) are used. Staining improves visualization and specificity but can alter or kill cells, while unstained preserves natural behavior.